Posted tagged ‘glacier’

Located in a deep canyon near Lost Lake, Sunshine Rock is a 700-foot monolith that would rival famous Beacon Rock in the Columbia Gorge, were you to set them side-by-side. The two rocks might even look a bit like twins: both feature walls of distinctive columnar basalt, and rise to a broad, fluted crest.

Despite its impressive size, Sunshine Rock is nearly hidden from view in the Lake Branch canyon, a few miles upstream from the West Fork Hood River. The rock briefly comes into view traveling down Lake Branch Road from Lost Lake, but only for a moment. With a little exploration, though, better views of this massive rock can be had from less-traveled routes in the area.

Sunshine Rock from Lake Branch Road

Sunshine Rock is a classic basalt plug — the solidified lava throat of an ancient volcano that was once a mountain. Geologic maps of the area identify the rock as andesitic basalt, dating back to the Miocene period of more than 7 million years ago.

This means that Sunshine Rock was formed as part of the “Old Cascades”, the range or deeply eroded peaks and ridges that pre-date today’s relatively young big volcanoes, like Mount Hood, by millions of years.

View across the Lake Branch valley to Sunshine Rock

Over the millennia, the Old Cascades have been carved by erosion and folded by fault lines, with countless new volcanoes emerging to cover older peaks in successive layers. Like most of the rock from the Miocene area, Sunshine Rock was buried by huge shield volcanoes of the Pliocene era, which dates back 2-5 million years.

Shield volcanoes are broad, gently sloped peaks that we now know as the mostly forested summits surrounding Mount Hood, including Larch Mountain, Lost Lake Butte, Mountain Defiance and several other volcanoes in the area. In the case of Sunshine Rock, nearby Indian Mountain is the overlying shield volcano that covers the older Miocene geology.

Giant firs give scale to one of the lower ramparts on Sunshine Rock

In more recent geologic times, the U-shaped valley of the Lake Branch was excavated by 7-mile long glacier that stretched from near present-day Lost Lake to the West Fork valley. There, it joined an enormous, 1,000-foot thick mega-glacier that extended 17 miles from Mount Hood to what are now the apple orchards of Dee Flat, along the Lost Lake Road.

The glacial period covers the Pleistocene era, which spans the most recent 2-million years, and numerous ice ages. The most recent ice advance peaked just 15,000 years ago, and was responsible for the most recent extent of the prehistoric Lake Branch glacier that exposed Sunshine Rock, along the flanks of the valley.

Recent History

Sunshine Rock seems to first appear in the modern record in early lookout tower survey photos. These photos were taken in the 1930s from new lookout sites, and include views from nearby Buck Peak, Raker Point and Lost Lake Butte. The view (below) from Raker Point in 1933 shows the rock most prominently, along with Indian Mountain in the background (another early lookout site).

The venerable Oregon Geographic Names doesn’t list Sunshine Rock among its thousands of entries, so short of historical files kept by the U.S. Forest Service, the inspiration behind the name may be lost to history. The name doesn’t appear on maps until the 1950s, suggesting that it came into being after the logging era was well under way, in the post-war period.

While the exact origin of the name is unknown, the thinking behind it seems evident: the position of the rock on a southeast facing valley wall allows it to catch morning sunlight, and thus would have been a bright beacon for nearby lookouts or loggers in the area.

Visiting Sunshine Rock

Forest Road 13 to Lost Lake forms a large loop, with Sunshine Rock located on the northern leg, along the Lake Branch Road segment of the loop. The best way to spot the rock is to approach from Lost Lake, winding down the Lake Branch valley, and watching for it through the trees.

You can also get a close-up view from Road 1330, which intersects Forest Road 13 near the rock, and leads to an abandoned quarry directly opposite the rock. For more adventurous explorers, Road 1320 climbs nearly to the top of the rock, with old logging spurs leading to the base of its cliffs.

It seems implausible, but climate change may be creating new glaciers on Mount Hood — but not in the usual way that glaciers are created. A close look at the retreating White River Glacier on the sunny south flank of Mount Hood reveals two stranded arms that are now separate glacier. As marked by (1) and (2) on the photo, above, a pair of truncated mini-glaciers have been cut off from the main flow of the White River Glacier by a previously hidden moraine that is now being exposed by the rapidly retreating ice.

Until fairly recently in geologic time, the White River Glacier extended far beyond its current extent, flowing down the rugged canyon shown in the photo for several miles to a terminus far beyond where Highway 35 now crosses the glacial outwash plain. But the glacier is retreating rapidly, destabilizing the canyon and changing its shape as it shrinks.

A closer look at two mini-glaciers on Mount Hood

A closer look at the two mini-glaciers reveals why a glacier is different from a static field of ice. Glaciers flow under their own weight, sending waves of ice sliding downward as more snow is added, above. Huge cracks known as crevasses form at stress points in the river of ice, and these are a defining feature in identifying a glacier. Both of these sheets of ice have crevasses, and thus are moving glaciers.

A look at the topographic map shows how the extent of the White River Glacier has changed as recently as the 1960s, when the map was surveyed. The mini-glacier marked as (1) was clearly an arm of the White River Glacier until very recently, but surprisingly, the second mini-glacier (2) appears to already have separated from the main glacier before the surveys were done — though it is clearly a truncated lobe of the main glacier, as well.

Another defining feature for this pair of mini-glaciers is that the emerging moraine that divides them from the main glacier also divides their outflow. They feed a separate branch of the White River from the main stem – another argument for recognizing these glaciers as discrete, perhaps?

It is logical to assume that these little glaciers are doomed by the same forces of climate change that created them, but there is a twist that just might keep them flowing — and perhaps thriving — as a result of climate change. While scientists believe that snow levels will rise in the Cascades over the next century, they also believe that precipitation will increase.

That could mean that in the highest elevation areas where winter precipitation still falls mainly as snow could actually see glaciers grow in depth, but perhaps not in length, since freezing levels would be higher. Therefore, if these mini-glaciers are high enough on the mountain, they may well survive, or possibly even grow, thanks to increased snowfall at this elevation.

If these glaciers are new, and independent of the White River Glacier, they deserve some respect, since all known glaciers in Oregon have been formally named. And that brings us to a bit of history surrounding this flank of the mountain. For here, on the upper slopes above these little glaciers, the first attempts on Mount Hood’s summit were made by early white settlers.

A close-up view of the mini-glaciers reveals classic crevasses

The first man in this story is Thomas Jefferson Dryer, the colorful publisher of the Weekly Oregonian in the mid-1800s (pictured below, on the left). Dryer claims to have been the first white man to climb the mountain, in August 1854. Dryer’s description of the climb makes it clear that he did not reach the true summit, though he may well have reached the top of the Steel Cliffs, only a few hundred feet below the summit — and an amazing achievement for the day.

Dryer complicated his case by embellishing the story with outrageous exaggerations — being able to see Mount Shasta (not possible) and peaks in the Rockies (definitely not possible), and his climbing companion bleeding form his skin from the extreme altitude (not very likely). But Dryer was also the first white man to climb Mount St. Helens, so his story must be taken with some degree of faith.

Dryer’s account wasn’t challenged until three years later, when one of his employees, Henry Lewis Pittock, made the first documented ascent of Mount Hood on August 6, 1857. The Pittock party made the climb along what is now the traditional southern route, skirting the west edge of the White River Glacier, and climbing through the crater. When Pittock’s party made claim to being the “first” to summit the mountain, it set off a dispute with Dryer over the veracity of his own account that continues to this day.

Thomas Jefferson Dryer (left) and Henry Lewis PIttock

In 1861, Dryer was tapped to serve in the Lincoln administration, and turned the Weekly Oregonian over to Pittock, to whom he owed a significant debt in the form of back pay. Pittock, in turn, converted the weekly into a daily and was soon publishing the predominant newspaper in the region, today’s daily Oregonian.

Pittock is now recognized as the first white man to summit Mount Hood, but like Dryer, doesn’t have a landmark in his name to record his place in history (though Portlanders are quite familiar with the iconic mansion he built atop the West Hills).

So I offer a modest proposal: honor both men for their historic climbs, with the western mini-glacier (1) named for Pittock, representing his more westerly approach, and the eastern mini-glacier named for Dryer, who may have even walked on this ice sheet in his own attempt at the summit. Both men deserve to be remembered for their part in Mount Hood’s history, and these little glaciers deserve some respect, too.

Reid Glacier, on Mount Hood’s rugged west flank, is one of the most interesting of the mountain’s 12 glaciers. This tumbling body of ice flows between the towering walls of Yocum Ridge and Hawkins cliffs, with the tall spire of Illumination Rock soaring above its deep crevasses. Oddly, Reid Glacier is the source of the Sandy River, whereas the Sandy Glacier gives birth to the Muddy Fork – some confusion on the part of early cartographers, perhaps? And while the Reid is among the most visible of Hood’s glaciers from Portland, few hikers actually make the long climb to the high meadows of Yocum Ridge for a close-up view of the glacier.

USGS view of the Reid Glacier

Reid Glacier is also unique as the only one of Mount Hood’s glaciers that wasn’t named for a local pioneer, or simply given a descriptive name. Instead, this secluded river of ice was named to honor Harry Fielding Reid, the eminent geophysicist who is considered to be the father of modern thinking on faults and tectonic forces.

Harry Fielding Reid (1859-1944)

Reid never actually visited the glacier, though he was an avid mountaineer and did study the White River Glacier extensively. The Mazamas honored Reid by naming the glacier for him at a campfire ceremony held on the mountain on July 16, 1901.

Harry Fielding Reid’s research took him around the world, and his groundbreaking work at Glacier Bay in Alaska was recognized by the naming of yet another Reid Glacier for the scientist. The Alaska glacier by the same name is much larger, of course, and is a tidewater glacier flowing into the Reid Inlet in Glacier Bay. Thus, the smaller Reid Glacier on Mount Hood lives in the shadow of its larger sibling in Alaska, with few biographies of Harry Reid making mention of the more diminutive Mount Hood namesake.

Today, the Seismological Society of America awards its top honor, the Harry Field Reid Medal, for outstanding contributions to the fields of seismology and earthquake engineering.